As the results of the examination of the measured data, it was found that the scattering of p_max/p_me is small, but that of p_s/p_me is considerably large, furthermore that of the degree of explosion p_max/p_c is extremely large which receives the influence of the dispersion of the all four parameters of p_max/p_me, p_s/p_me, V₁/V_H and V₂/V_H. The scattering of p_max/p_c of each group against p_me/p_me0 are shown in the figures (a) to (c) in Fig. 8.

Here, it was assumed that α, β, γ and δ mean the sensitivity factor of the four parameters of p_max/p_me, p_s/p_me, V₁/V_H and V₂/V_H to the T_max respectively and the changing ratio of T_max (T_max/T_max0) could be described as the following equation.

These sensitivity factors were calculated by the performance simulation analysis under conditions that the altering ranges of each parameter are set as those in the figure (a) to (d) in Fig. 6, the reference points of each parameter are set as the average value and each parameter is altered independently. The results are as follows.

α=0.0727, β=-0.518, γ=-0.600, δ=0.0364　　　(3)

As seen from the above calculation results, the sensitivity factors of p_s/p_me and V₁/V_H are negative and those of p_max/p_me and V₂/V_H are positive, and the former absolute values are greater than those of the latter over one figure. The reason of it is considered that p_s/p_me and V₁/V_H are closely related to the gas quantity G₁ at the beginning of the compression which controls T_max by diluting the supplied heat and the heat generated in the cylinder.

Here p_max/p_c is described as bellow.

In this equation, since the parameters with the positive sensitivity factor exist in the numerator and those with the negative sensitivity factor exist in the denominator, the change of p_max/p_c due to the dispersion of the performance parameters should correspond well to the change of T_max. Consequently, the change of p_max/p_c is considered to correspond well to the change of NOx. Then the relation between the p_max/p_c and NOx on the data of A-1 type engine is examined which include many data in the same rating. The result is shown in the figure (d) in Fig. 8. It is found from this figure that they have relatively well proportional relation.

　

4.2 The relation between NOx and p_max/p_c

In case of this discussion, the change of T_max due to the alteration of engine rating is small, as already shown in the figure (e) in Fig. 6. Also, the rate of the dispersion of p_max/p_c in the measured data is larger exceedingly than the change by the engine rating, as shown in the figures of (a) to (c) in Fig. 8.

(a) Dispersion of P_max/P_c (group I)

(b) Dispersion of P_max/P_c (group II)

(c) Dispersion of P_max/P_c (group III)

(d) Relation between NOx and P_max/P_c(A-1 type)

Fig. 8 Dispersion of p_max/p_c at shop trials and relation between NOx and p_max/p_c

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